April 23 (Reuters) - A U.S. federal judge in Missouri on

Tuesday preliminarily approved an antitrust class-action

settlement that requires the National Association of Realtors to

pay $418 million and implement changes to how Americans buy and

sell homes.

WHY IT'S IMPORTANT

U.S. District Judge Stephen Bough's settlement order marked

a key first step in a months-long process that will culminate in

a final approval hearing set for Nov. 26 in Kansas City,

Missouri.

The plaintiffs' lawyers who negotiated the deal have

heralded it as a game-changer for how homes are bought and sold

in the United States.

Under the terms of the settlement, home sellers will no

longer be required to offer a commission to buyers' agents in

order for their properties to appear on "multiple listing

services," which is where most home sales originate. Commissions

still can be negotiated as part of the process.

CONTEXT

Bough presided over a trial last year that ended in a $1.8

billion verdict against the National Association of Realtors and

other defendants. A class of home sellers accused the defendants

of unlawfully inflating the commissions they pay to agents for

buyers.

The National Association of Realtors has long defended the

industry's commission practices, arguing they promote efficiency

and transparency in residential home-buying. The Chicago-founded

trade group, which did not admit any liability as part of its

settlement, welcomed Bough's preliminary approval in a statement

on Tuesday.

Brokerage company HomeServices is the only remaining

defendant in the case. The company has asked Bough to overturn

the verdict.

BY THE NUMBERS

The deal is the largest reached so far in litigation over

real estate commissions, pushing total proposed settlements to

$626 million. Anywhere Real Estate ( HOUS ) separately said it would pay

$83.5 million, Compass agreed to pay $57.5 million and Re/Max

settled for $55 million.